If I remember correctly, trade route values are determined by (1) the length of the trade route, (2) the age of the trade route, and (3) the incomes of the starting and ending planets. So you want a planet that is far away from where you want to send the freighter, and one with a high planetary income. In Crusade, the income is determined by raw production modified by improvements and star base effects.

There was a change in GC3 at some point, maybe Crusade only, where the diplomatic bonus from trade only applies to civs that have certain trading/economic traits. I'm not clear on which civs have that bonus and which don't, although I think that the Iridium definitely have it.

There was a change in GC3 at some point, maybe Crusade only, where the diplomatic bonus from trade only applies to civs that have certain trading/economic traits. I'm not clear on which civs have that bonus and which don't, although I think that the Iridium definitely have it.

It could be that I haven't gotten the needed Techs. I will pay closer attention to that. Thanks!